ABSTRACT
The steep fall in the costs associated with solar photovoltaic (PV) and wind turbines has brought two of South Africa's other impressive natural resources – solar and wind – into sharp relief. The 2016 South African study found solar PV, rather than wind, to be the main driver for 15-minute gradients in the residual load, owing to the astronomical movement of the sun, which results in a bell-shaped output curve. Flexibility has increased and will continue to increase as wind and solar PV emerge as the default technology choice for low-cost bulk energy in the electricity sector. There are always two distinct times in a power system: times of undersupply from solar PV and wind power, and times of oversupply of solar PV and wind power. Wind and solar PV will reduce the quantity of power produced from fossil-fuel plants, along with their capacity factors and operating hours.
